Wave guide regulator



y 1951 R. G. GARFITT 2,553,649

WAVE GUIDE REGULATOR Filed Aug. 5, 1947 'IIIIIIIIII'I'IIII'llocal osc.

A horney Patented May 22, 1951 OFFICE WAVE GUIDE REGULATOR Richard G. Garfitt, Sale, England Application August 5, 1947, Serial No. 766,354 In Great Britain October 22, 1945 Section 1, Public Law 690, August 8, 1946 Patent expires October 22, 1965 Claims. 1

This invention relates to ultra-high frequency electrical apparatus and is more particularl concerned with arrangements comprising an electromagnetic wave guide.

An object of the invention is to provide an improved device for regulating the electromagnetic energy passing through a wave guide.

A further object of the invention is to provide an arrangement for use as a means of stabilising the electromagnetic power passing through a wave guide at a desired predetermined level.

Another object of the invention is to provide an arrangement by which the output of a rectifying device such as a crystal mixer, whose conversion efficiency is subject to variation, may be stabilised at a desired predetermined level.

Yet a further object of the invention is to provide an arrangement by which amplification of a Weak direct current may be eifected.

The arrangement according to th invention comprises a coil of conducting material mounted within an electromagnetic wave guide and free to rotate about an axis perpendicular to the axis of the coil, said coil being so shaped and dimensioned that bodily it forms an obstacle resonant to electromagnetic ener y passing through the wave guide; biassing m ans for urging said coil towards a predetermined position and means for producing a magnetic field surrounding said coil whereby by the application of a direct current to the coil winding, the resonant obstacle formed thereby may be rotated on the said axis against the action of said biassing means to control the flow of electromagnetic energy through the wave guide. The control of electromagnetic energy flowing through a wave guide by means of a resonant obstacle is described and claimed in copending United States application Serial No. 763,621, filed July 25, 19 17 as the equivalent of corresponding British Specification No. 597.216, filed April 20, 1944, and accepted in Great Britain on January 21, 1948. The coil may be arranged for movement against the action of control means such as hairsprings or alternatively may be supplied with a suitable opposing current derived from a constant D. C. source.

In a preferred form the coil winding is adapted to form a closed resonant ring of the kind described in the aforesaid copending United States application Serial No. 763,621, filed July 25, 1947 as the equivalent of corresponding British Specification No. 597,216, filed April 20, 19 A, and accepted in Great Britain on January 21, 1948 whereby it allows substantially unimpeded transmission of energy when disposed with its own plane parallel with that of the axial direction of the guide and eifects substantially complete cut-off of energy when disposed with its plane normal to the said axial direction.

A number of arrangements embodying the invention will now be described by way of example with reference to the accompanying drawings in which:

Figure l is a semi-diagrammatic cross sectional view and Figure 2 is a similar sectional elevational view of an arrangement for stabilising the electromagnetic power flowing through a wave guide.

Figure 3 is a View similar to Figure 1 of an arrangement for stabilising the rectified output of a crystal mixer at a predetermined level, while Figure 4 is a diagram showing an arrangement for efiecting amplification of a weak direct current, and

Figure 5 shows an arrangement for use as a remote controlled regulator for controlling the power flowing through a waveguide.

Referring first to Figs. 1 and 2, the device comprises a multi-turn rectangular coil winding ll rotatably mounted on pivots l2 within a rectangular wave guide it, The guide carries a wave of the H10 mode between a source connected beyond the end a and a load at the opposite end 19. The axis of rotation of the coil is perpendicular to the E-veotor of the wave and to the longitudinal axis of the guide.

The dimensions of the cell are such that, bodi- 1y, it forms a resonant closed ring of the kind described in the aforesaid copending United States application Serial No. 753,621, filed July 25, 1947 as the equivalent of corresponding British Specification No. 597,216, filed April 20, 1944, and accepted in Great Britain on January 21, 19 .3 and serves to allow substantially unimpeded transmission of power through the guide when disposed with its plane parallel with the axial direction of the guide while effecting substantially complete cut-off of power transmission when disposed with its plane normal to said axial guide direction.

Electrical connection is made to the coil winding through two very light hairsprings i3. A permanent magnet having opposed poles M provides a magnetic field normal to the axis of rotation of the coil I l.

A crystal detector ll is connected to a probe 58 coupled loosely to the guide it by insertion through a suitable aperture on the load side I) of the coil. The rectified crystal current is passed through the coil H by way of choke coil l9,

opposition to a steady current derived from a stabilised D. C. source 55 flowing through a high resistance 16. The arrangement is such that increase in rectified crystal current turns the coil in a direction so as to cut down the power transmitt-ed therepast, i. e. so as to reduce the crystal current. Obviously the probe 58 may be replaced by any other known form of electromagnetic pick-up device such as a loop.

Assuming the coil H to be perfectly free, it ma turn until no current flows through it, i. e. until the crystal current is exactly equal to that from the source is. The crystal current is a function of its rectifying efficiency and the power supplied to the load; assuming the crystal has a constant characteristic, the power supplied will accordingly be held constant. Alteration of the value of the counter-current supplied by the source 15, e, g. by variation of resistance H3, affords a control of the value of power supplied. In practice, the control exerted by the hairsprings I3 is not zero and an out-of-balance current must flow through the coil; this need not exceed a few micro-amperes, however.

In the arrangement shown in Fig. 3, the construction is substantially identical with that described above with the exception that the crystal rectifier Ila, now connected directly across the coil winding, is that forming part of the crystal mixer device whose rectified D. C. output is required to he kept constant in spite of variations of the characteristics of the crystal. The wave guide H3 conveys electromagnetic energy from the local oscillator 28 to a crystal mixer and the coil winding H is arranged to turn within the guide so as to maintain the power supplied by the local oscillator at an intensit such that the rectified current from the crystal is at a desired redetermined level. Adjustment of the power flowing through the wave guide from the local oscillator is effected by adjusting the D. C. current applied to the coil from a D. C. source 36.

Fig. 4 shows a D. C. amplifier arrangement. A length of wave guide Ilia is arranged so as to divide into two sections tub, Hlc whose other ends are joined to form a closed loop. At the throat of the division point of the guides is arranged a moving coil winding Ha shaped to form a resonant ring similar to that already described. This ring, by its movement into different positions of inclination with respect to the divergent guide portions, serves to vary the ratio of the E. M. energy values supplied from the end a! to the respective guide porticm A probe ifia connected toa crystal rectifier. is located at point in the wave guide loop such that the path length by way of one fork, e. g. lfib, is M2 or an odd multiple thereof longer than the path length by way of the other fork.

With the moving coil in a position such that equal division of energy is made between the two paths, the rectified output from iSa ll be zero owing to the cancellation eiiect ca sed by the 180 phase displacement of the two wave components reaching it from opposite directions. Movement of the coil I la, by a curent of the order of microamperes applied by way of terminals T. and T2 thereto, from such position will upset the balance between the two branches and so provide a resultant wave component at the probe l3a which, after rectification in rectifier lib, may give rise between terminals T3 and T4 to a current of the order of milliamperes.

Figure 5 shows an arrangement substantially identical to the arrangement shown in Fig. l

in which, however, the rectifier and counter current source is replaced by a source of current IS. The arrangement ma be used as a remote controlled power regulator since the position of the coil H within the waveguide and thus the power flowing through the waveguide may be controlled by varying the current applied to the coil from source 19.

I claim:

1. An arrangement for regulating the electromagnetic energy fiowing through an electroma netic wave-guide comprising, an electromagnetic wave-guide, a coil of conducting material rotatably mounted within said wave-guide on an axis perpendicular to its own axis, said coil being resonant to electromagnetic energy flowing through said wave-guide, magnetic field producing means producing a magnetic field surrounding said coil, an electromagnetic pick-up device coupled to said wave-guide at a position beyond the coil in the direction of flow of electromagnetic energy, a rectifier rectifying the electro magnetic energy in said pick-up device, electrical connections applying the rectified current output of said rectifier to said coil in a sense tending to decrease the electromagneti energ passing said coil, 21. source of electrical current, and electrical connections applying current from said source of electrical current to said coil in opposition to said rectified current output of said rectifier.

2. An arrangement for regulating the fiow of electromagnetic energy through an electromagnetic wave-guide according to claim 1 wherein said rectifier is a crystal rectifier.

3. An arran ement for regulating the electromagnetic energy flowing through an electromagnetic wave-guide comprising, an electromagnetic wave-guide, a coil of conducting material rotatably mounted within said wave-guide on an axis perpendicular to its own axis, said coil being a closed ring which is resonant to electromagnetic energy passing through said wave-guide, magnetic field producing means producing a magnetic field surrounding said coil, an electromagnetic pick-up device coupled to said wave-guide at a position beyond the coil in the direction of flow of electromagnetic energy, a rectifier rectifying the electromagnetic energy in said pick-up device, connections applying the rectified current output of said rectifier to said coil in a sense tending to decrease the electromagnetic energy passing said coil, a source of electrical current and connections applying current from said source of electrical current in opposition to said rectified current output of said rectifier.

l. An arrangement for regulating the electromagnetic energy flowing through an. electromagnetic wave-guide comprising an electromagnetic Y wave-guide, a coil of conducting material rotatably mounted within said wave-guide on an axis perpendicular to its own axis said coil being resonant to electromagnetic energy passing through said wave-guide, magnetic field producing means producing a magnetic field surrounding said coil, hairsprings urging said coil towards a predetermined position and making electrical connection to the two ends of said coil, an electromagnetic pick-up device coupled to said waveguide at a position beyond the coil in the direction of flow of electromagnetic energy, arectiiicr rectifying the electromagnetic energ in said pick-up device whose rectified current output is applied through said hairsprings to said coil in a sense tending to decrease the electromagnetic energy passing said coil, and a source of current feeding said coil REFERENCES CITED to we rectified Qurrent Output of The following references are of record in the i l r i e i ri angement for e ulatng the el ctro me of this patent:

.L g 1 '3 magnetic energy flowing through an eiectromag- 5 UNITED STATES PATENTS netic waveguide comprising in combination With Number Name Date the electromagnetic waveguide of a coil of con- 879,081 Pierce Feb. 11, 1908 ducting material rotatabiy mounted on an axis 1,877,008 Miller Sept. 13, 1932 perpendicular to its own axis, said coil being reso- 2,129,712 Southworth Sept. 13, 1938 nant to electromagnetic energy flowing through 0 2,294,942 Varian Sept. 8, 1942 said Waveguide, magnetic field producing means 2,368,701 Borden Feb. 6, 1945 producing a magnetic field surrounding said coil, 2,396,044 Fox 1 Mar. 5, 1946 an electromagnetic pick-up device coupled to said 2,405,049 Pattee July 30, 1946 Waveguide at a position beyond the coil in the 2,431,103 Bradley Nov. 18, 1947 direction of flow of electromagnetic energy, 2:. rec- 15 2, 4 ,598 Robertson M y 18, 1948 tifier rectifying the electromagnetic energy in 4 ,614 Norton June 1, 1948 said pick-up device, electrical connections appiy- 8 ,18 Irving Aug. 30, 1949 ing the rectified current output of said rectifier ,5 Hansen Apr. 4, 1950 to said coil in a sense tending to decrease the 2,505,534 Fiske Apr. 25, 1950 electromagnetic energy passing said coil, and resilient means biasing the coil in a sense opposite to the first-named sense.

RICHARD G. GARFITT. 

